5
8393CS-MCU Wireless-09/14
ATmega256/128/64RFR2
The device is manufactured using Atmel’s high-density nonvolatile memory technology.
The On-chip ISP Flash allows the program memory to be reprogrammed in-system
trough an SPI serial interface, by a conventional nonvolatile memory programmer, or by
on on-chip boot program running on the AVR core. The boot program can use any
interface to download the application program in the application Flash memory.
Software in the boot Flash section will continue to run while the application Flash
section is updated, providing true Read-While-Write operation. By combining an 8 bit
RISC CPU with In-System Self-Programmable Flash on a monolithic chip, the Atmel
ATmega256/128/64RFR2 is a powerful microcontroller that provides a highly flexible
and cost effective solution to many embedded control applications.
The ATmega256/128/64RFR2 AVR is supported with a full suite of program and system
development
tools
including:
C
compiler,
macro
assemblers,
program
debugger/simulators, in-circuit emulators, and evaluation kits.
3.2 Pin Descriptions
3.2.1 EVDD
External analog supply voltage.
3.2.2 DEVDD
External digital supply voltage.
3.2.3 AVDD
Regulated analog supply voltage (internally generated).
3.2.4 DVDD
Regulated digital supply voltage (internally generated).
3.2.5 DVSS
Digital ground.
3.2.6 AVSS
Analog ground.
3.2.7 Port B (PB7...PB0)
Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each
bit). The Port B output buffers have symmetrical drive characteristics with both high sink
and source capability. As inputs, Port B pins that are externally pulled low will source
current if the pull-up resistors are activated. The Port B pins are tri-stated when a reset
condition becomes active, even if the clock is not running.
Port
B
also
provides
functions
of
various
special
features
of
the
ATmega256/128/64RFR2.
3.2.8 Port D (PD7...PD0)
Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each
bit). The Port D output buffers have symmetrical drive characteristics with both high sink
and source capability. As inputs, Port D pins that are externally pulled low will source
current if the pull-up resistors are activated. The Port D pins are tri-stated when a reset
condition becomes active, even if the clock is not running.
Port
D
also
provides
functions
of
various
special
features
of
the
ATmega256/128/64RFR2.
3.2.9 Port E (PE7...PE0)
Port E is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each
bit). The Port E output buffers have symmetrical drive characteristics with both high sink
and source capability. As inputs, Port E pins that are externally pulled low will source
